Force pump



M. W. TUTT.

FORCE PUMP.-

APPLICATION FILED JULY 22' I921- 1,41 3,205. n ed. p 18, 1922. v

I 6 SHEETS-SHEET l- M. W. TUTT.

FORCE PUMP. I APPLICATION FILED JULY 22, I921- Patented Apr. 18, 1922.

6 SHEETS-SHEET 2- M. W. TUT'L' FORCE PUMP.

APPLICATION rim) JULY 22, um.

6 SHEETS-SHEET 3- 1,413,205. Patented pr- 18, 1922.

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FORCE PUMP. APPLICATION flLEQ JULY 22, I92].

I 1 413 205 Patented Apr. 18, 1922.

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M. w. TUTT. ronc: PUMP. APPLICATION FILED JULY 22, 1921.

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MONTAGUE, winniniu Tom, on LONDON, ENGLAND, Assie rNon or ONn-IihLi Tb HULBURIJ ENGINEERING company, LIMITED, or LONDON, ENGLAND.

FORGE PUMP;

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Specification of Letters Patent. 18,

Application filed July 22, 1921. Serial No. 486,800.

(GRANTED UNDER THE PROVISIONS or THE ACT or MARCH 3, 1921, 41sTAT. Li, 1313 To all to item it may concern V v Be it known that LluONTAGUEdVILLIAM TU'rT, a subject of the King of Great Britain, residing at St, Benet Chambers, Fenchurch Street, London, England, have:invented new and useful Improvements in Force Pumps, (for which I have filed'an application in Great Britain July6, 1920, No. 157,692,) of which the following is a specification.

This invention relatesto force-pumps for compressing air or gas and feeding or displacing liquids, of the kind wherein the pump body or cylinder is provided withtwo pistons orplungers differentially movable in the same direction, between which the charge is compressechtherod of one plunger extending through the rod of theother plunger, the object of the invention being to provide an improved pump of this type in which the .usual suction and back-pressure or non-returnvalves are dispensed with.

' According to. the invention the improved pump comprises a cylinder having inlet and outlet ports and a pair of plungers designed to be reciprocated in the said cylinder, the suction and compression space being provided between the said plungers. F or this purpose the outer or upper plunger is maintained stationary for a portion, said one third, of each stroke whilst the lower orinner plunger is moving to draw in acharge through theinlet port. The two plungers then move together for the remaining portion of the stroke which brings the induced charge opposite the outlet-port. On the return stroke the outer or upper plunger is again held stationary for the first portion of the stroke, whilst the lower or inner plunger is drawn towards it to expel the charge through the outlet port after which the two plungers move together for the remaining portion of the stroke when the operation begins de novo. i

To operate the plungers I advantageously make use of the following arrangen ient, that is to say, the rod of the inner or lower plunger is reciprocated by a cross-head actuated by a crank on a crank-shaft which also carries a cam-plate rotating therewith, the said cam-plate having two cam surfaces diametrically opposite to one another which bear against a roller attached to the upper or outer. a gs; thatyaiadingj a an plunger stationary for the periods required. The downward or inward movement ofthe outer or upper plunger is positively efi'ectedby an extension piece on the cross-head,

whilst the return movement thereof is effected by the inner or lower plunger. I The pump may be eitherof the singleacting type or of the,tandem type o-r in they form of two sets of tandem pumps placed side by side or two sets of four pumps may be arranged one on eachside,ofthe centre line of the crank-shaft all the plungers being controlled by a single crank and cam.

To enable the invention to be fully understood, I will describe it by, reference to the accompanying drawings, in which z Figures 1, 2, 3, 4 and 5 are sectional elevations of a single-acting pump, constructed. according to theinvention and showing the parts in the different positions they occupy duringa complete stroke ofthe plungers, and l Figure 6 is a sectional View illustrating a multiple dolilble-acting pump.

a indicates the upper or outer plunger, Z) the lower or inner plunger and cthe cylinder in which the said plungers ,are reciprocated. ,e is the inlet port to the cylinder 0 and fthe outletor discharge port therefrom. g is the rod of the inner or lowerplunger b, the said rod passing axiallythrough the plunger a and i is the. cross-head to which the outer endof the rod 9 is attached. This cross-head h is reciprocated by means of a slide-block 0 which. moves in a slot p in the said cross-head h, the said block '0 being carried by the crank-pin n of the crank-shaft 12 (Z is the extension piece provided onv the cross head h for positively actuating the plunger a.

m indicates the cam-plate which is secured to, so as to rotate with, the crank-shaft n and la and Z are the two cam surfaces pro vided thereon, these two surfaces being curved to arcs of circles concentric with the crank-shaft. is the roller which is attached to the outer end of the plunger a the said roller coacting with the cam surfaces.

The plungers a and Z) and the plunger rod 9 are provided With' peripheral packing groovest and, the plunger ais prevented from rotating'in the cylinder by means of the longitudinal groove 1* with which engages a set-screw g projecting inwardly from the cylinder wall.

The pump operates as follows, that is to. say, at'the beginning of a stroke the parts are in the position shewn in Figure 1, the inner end of the plunger a being approximately coincident with the outer edge of the inlet port 6 and the plunger 1) being in contact with the plunger a. In this posi tion of theparts the roller j is just in contact with the front end of the inner surface a space formed between the plungers.

of the cam 70. When, now, the crank-shaft 41 rotates in the direction of the arrow the plunger 7) is moved inwards, the plunger a eing-held stationary by the cam is and is so'held until the said cam has passed out of contact with the roller-j during which period the movement ofthe plunger 7) has drawn a charge through the inlet e into the This position of the parts is shown inFigure 2 in which the extension piece d of the crosshead is in contact with the outer end of the plunger a so that for the remaining portion of the stroke the two plungers move together into the position SllOWIllIl Figure 3 in which the inlet port 6 is completely closed by the plunger a and then into the position shewn in Figure 4: in which the space between the plungers is fully opened to the outlet port f andtheroller j has made contact with the outer surface of the cam Z.

The continued rotation of the crank-shaft portionof the stroke the two plungers move together until-the cam 70 again engages with the roller 7' when the operation begins de novo.

In -Figure 6 I have illustrated the application of the invention to a tandem pump formed of four double-acting pumps. In this construction the operation of which is identicaljw-ith that shown in Figures 1 to 5 I each cylinder is provided with one plunger which acts in conjunction with a pair of plungers a and all four plungers I) are connected to and operated by a common crosshead it whilst the plungers e are controlled by a single cam-plate m. Theinlet ports 6 of each unit may be coupled together'as "also may the outlet ports f thus providing a set'of four double acting pumpsinst'ead of right separate pumps. In this arrangement it'will be noticed thatthe plungers a are operated entirely by contact with the plungers'b; 1

Claims.

1. A force pump comprising a cylinder having inlet and outlet ports, a pair of plungers reciprocable therein and means for retaining the upper or outer plunger stationary for a portion of the inward and outward strokes andfor moving the said plungers together for the remaining portions of the strokes so as to draw in a charge between the plungers and expel it therefrom, the movement of one plunger being effected by the movement of the other plunger.

2. A force pump as claimed in claim 1, wherein the rod of the inner or lower plunger extends through the upper or outer plunger and is reciprocated by a crank-shaft which carries a cam-plate havingtwo cam surfaces designed to engage andhold the upper or outer plunger, the inward and outward movements of which are effected by the inner plunger, substantially as described.

3. In a force pump the combination-with a cylinder having inlet and outlet ports, of a pair of plungers reciprocable therein, a crank shaft and crank, connections from the crank to one. of said plungers, having a part, extending through the other plunger, and provided with means for engaging and moving the latter plunger in one direction, its movement in the opposite direction being effected by the crank actuated plunger and means operable in timed relation with the crank shaft for holding the second men tioned plunger stationary during portions of the reciprocating movements of the first mentioned plunger.

4. In a force pump the combination with a cylinder having inlet and: outlet ports of a pair of plungers reciprocable therein, a crank shaft and crank for operating'both plungers, connections fromsaid crankto one plunger provided with a part extending through and having a sliding engagement with the other plunger, and'provided with means for-positively operating the latter plunger in one direction, its movement in the opposite direction being effected by the crank actuated plunger,v a cam on the crank shaft provided with cam faces for holding the second mentioned plunger stationary during'a portion of the reciprocating movements of the first mentioned plunger in both a pair of plungers reciprocable therein, a plungerrod connected to one of said plungers and extending through and having a sliding engagement with the other plunger,

said rod having apart for engaging and c moving the latter plunger, a crank shaft and crank, said crank being operatively connected to said plunger rod, a cam on said crank shaft provided with a pair of separated cam surfaces and a roller on said second mentioned plunger for engaging said cam surfaces, to hold the said plunger stationary during portions of the movement of the other plunger in both directions.

6. In a force pump the combination with a cylinder having inlet and outlet ports, of a pair of plungers reciprocable therein, a

plunger rod connected to one of said plungers and extending through and having a sliding engagement with the other plunger, said rod havlng a part for engaging and moving the latter plunger, a crank shaft, and crank, a cross head secured to said plunger rod, and engaging apart connected with said crank, a rotary cam operated in timed relation with the crank shaft, and provided with two separated cam surfaces, and a friction roller connected with said second mentioned plunger for engaging said cam surfaces to hold the said plunger stationary during a portion of the movement of the first mentioned plunger in both directions.

MONTAGUE WILLIAM TUTT. 

